This invention relates to the field of modular retaining walls, particularly to the development of replaceable plates designed to provide a decorative facing on a modular retaining wall.
The recent development and advancement in the field of modular retaining walls has been a boon to the do-it-yourself homeowner and the small contractor. Modular retaining walls, also known as mortarless wall or dry stack wall systems, allow the creation of retaining walls without using mortar between the bricks or blocks. In place of mortar, modular retaining walls blocks rest directly upon a lower layer of blocks. The lowest layer is typically buried or partially buried in earth. As in all retaining walls, the back side of the wall is back-filled with the dirt being retained. The retained earth tends to push the wall forward. In modular retaining walls, the blocks are prevented from sliding relative to one another due to a lip incorporated into each block, or through the use of pins that at least partially traverse two adjoining blocks. In most cases, the modular retaining wall is constructed so that each successive layer of modular blocks is placed on the lower level slightly to the rear of center, so that the entire wall leans backwards into the earth being retained.
If the retaining wall is short enough (generally about four feet tall), the wall is typically constructed as a gravity wall. Gravity walls rely on the weight of the modular retaining wall blocks and the slight backward lean of the wall described above to prevent the wall from tipping due to the force of the back-filled dirt. Modular retaining walls may also be used to construct taller walls. In these cases, the wall is generally reinforced by additional means such as the geogrid tie-back sheet described in U.S. Pat. No. 4,914,876 to Forsberg. However, even reinforced modular retaining walls still have the general characteristic of modular blocks resting directly on a lower row of blocks without the use of mortar.
Typically, modular retaining wall blocks are formed by molding a colored concrete mixture into the desired shape. The front face of each block, which forms part of the wall face when the retaining wall is completed, is generally given a rough hewn look so as to simulate split rock. Alternatively, the block could be molded with a flat front face that gives a simulated brick wall appearance to the finished wall.
Unfortunately, this method of creating a decorative face to a modular retaining wall limits the variety of looks that such a wall can have. The rough hewn face is widely used, leaving many users hoping for a more distinctive look to their wall. In addition, the flat front face of a colored concrete block cannot successfully duplicate the rich colors and ordered pattern created by a brick and mortar wall.
The color and texture of modular blocks can be overcome by producing the blocks through a process other than molded concrete. For instance, modular wall blocks could be made entirely out of more attractive (and expensive) materials such as marble or clay. However, since modular retaining walls depend upon their size and weight to hold back the retained wall, making the blocks out of a more attractive material quickly becomes prohibitively expensive.
It is possible to manufacture a more decorative facing directly onto the block. In U.S. Pat. No. 3,687,771 to L. Meijer, a method was disclosed for constructing a concrete block with a plastic or paper base laminate for the front face. Applying this technique to modular retaining blocks would allow the majority of the block to be formed of less expensive materials. The facing could be molded into the main body of the block, as explained in the U.S. Pat. No. 3,687,771 patent, or could form part of an offset facing section, as described in U.S. Pat. No. 3,290,849 to Wright.
Regrettably, the use of a modular retaining wall block that has a more expensive decorative facing molded to its front creates several problems. First, the creation of a multi-component block involves the expensive process of securing the facing to the remainder of the concrete block. For instance, the method described by L. Meijer utilizes a complicated process of applying different resin layers to the block, as shown in FIGS. 2 and 5.
In addition, the facing itself is susceptible to damage during storage and shipping of the block, and during the construction of the modular retaining wall itself. The cost of constructing such a wall would be increased either by the cost of preventing damage to the block face (through the use of a removable pad), or by the cost of blocks damaged during shipment and construction.
Finally, a molded-on face has the disadvantage of being permanently attached to the modular block. If alternative facings are to be offered for sale at a retail outlet, the outlet must stock a large inventory of modular blocks that differ only in the facing applied. The permanency of a molded-on face also prevents the re-facing of an existing wall at a later date.
What is needed is a method for removably attaching a face plate to a modular retaining wall after the wall has been constructed. Unfortunately, known methods for facing an existing wall cannot be adapted for modular retaining walls, as seen below.
One technique for facing a wall is through the creation of a simulated brick, stone, or tile wall panel, as exemplified in U.S. Pat. No. 4,644,719 to Salazar, and U.S. Pat. No. 3,740,910 to Taylor et al. In these techniques, a large panel of the desired look, such as a simulated brick wall, is constructed so as to be easily attached to a wood, or concrete block wall. However, such panels could be applied only to walls with large, flat areas on which the panels could be affixed. One of the primary advantages of modular retaining walls is their ability to create gracious, curving walls; walls that would be unsuitable for receiving a wall panel.
A second alternative is to affix standard wall or floor tiles to the modular wall. The use of wall tiles is well known, an example of which can be found in U.S. Pat. No. 3,962,504 to Sherwin. Unfortunately, most modular retaining wall blocks have rough hewn faces, and therefore do not contain a surface upon which the tile can be affixed. Alternatively, flat face blocks generally have enough decorative texture in the mold as to prohibit the creation of the good adhesive bond with the tile. Even if an effective bond to the tiles could be formed, tiles cannot be attached effectively since the misalignment of adjacent stones prevent tiles from being attached across multiple stones. Finally, standard methods of affixing tiles do not allow for the later removal and replacement of tiles, a benefit that would be useful in cases of tile damage or a desire for a different wall appearance.
A third alternative for facing a preexisting wall is to form a decorative facing cap that fits over each block, as described in U.S. Pat. No. 5,465,544 to Ghahary. In this technique, a facing cap for blocks such as bricks or cinderblocks is formed with a lightweight sheet having dimensions marginally larger than the block and a lip that extends upward from the sheet edges. The facing cap slips over the entire face of the block, and is held in place by the lips which grab the sides of the block, as shown in FIG. 3 of U.S. Pat. No. 5,465,544. Additionally, the cap can be held in place with adhesives. Although novel, this technique cannot be applied to modular retaining walls. Since modular walls are formed without mortar, individual blocks rest directly on top of and adjacent to one another. Because of this direct contact, the lips found on the facing cap of U.S. Pat. No. 5,465,544 would be unable to grasp the edges of the modular wall block.
The present invention overcomes these limitations in the prior art by providing a face plate that can be removably attached to a modular wall after the modular wall blocks are positioned into place.